Chinese JoineryChinese Joinery
中文
Legs, tops and aprons
后足穿椅盘
hòuzú chuān yǐpán

Chair Leg Through the Seat (椅子后足穿过椅盘): Ming Chair Construction

Leg through the seat · 腿足贯穿面子

By · Updated

Above the seat it is a back post; below it, a leg. In a Ming chair they are one piece of wood.

The seat frame is threaded onto it.

Chinese
腿足贯穿面子 · tuǐzú guànchuān miànzi
Joins
Leg and seat frame
Found in
Armchairs, some stands and lamp stands
Signature parts
Continuous leg · holes in the seat frame
Compare
Through tenon
Drag to rotate. Slide to take the joint apart, or press Assemble to watch it go together.

How it works

One piece from floor to back

In an ordinary armchair the seat frame is mitred and tenoned together and bored at its four corners; the front and back legs pass through these holes. The parts above and below the seat look separate, but each upright is continuous. Wang Shixiang calls this the strongest arrangement.

Round above, square below

Some chairs are round above the seat and square below. Most seats are slid down over the legs from the top, but in a few chairs a squared section of the leg locks into a square hole, so the seat frame must be opened to take it apart.

Proportions in the model are illustrative.

How it's made

  1. One piece
    Step 1

    One piece

    Leg and back post are one piece.

  2. Continuous
    Step 2

    Continuous

    A continuous back leg.

  3. Hole
    Step 3

    Hole

    A hole at the seat corner.

  4. Frame
    Step 4

    Frame

    The seat frame is joined first.

  5. Slide down
    Step 5

    Slide down

    The seat slides down over the leg.

  6. Through
    Step 6

    Through

    The leg carries straight through.

Variations

Square lock

A squared section of the leg locks into a square hole in the frame.

Separate arm post

Sometimes the front arm post is a separate piece; this is weaker.

Can you CNC this?

Possible, with design or setup changes

The round holes in the seat frame are simple to bore. The continuous curved back leg is long and may need a 4th axis or a lathe for its round section.

Free STL downloads (one file per part)

Before cutting or printing, read the CNC and 3D-printing notes on tool radius, scaling the STL files and their licence.

In museum collections

Roundback armchair, 1600s–1700s, 1600s–1700s, Cleveland Museum of Art, accession no. 1955.40.1
Roundback armchair, 1600s–1700s
Cleveland Museum of Art

Where you’ll see it

  • Roundback armchair · Legs through the seat: Back legs run up through the seat frame and tenon into the yoke; the front posts do the same, each cut from one piece.

Questions

Is the back post a separate piece?

No, it is the same timber as the leg.

How does the seat go on?

It is bored and slid down over the legs.

Is it strong?

It is the strongest arrangement for a chair.

Further reading
  1. Roundback armchair, 1600s–1700s, Cleveland Museum of Art (collection record)
  2. 王世襄《明式家具研究》（Wang Shixiang, Research on Ming Furniture），第 117 页
  3. 王世襄《明式家具研究》（Wang Shixiang, Research on Ming Furniture），第 116 页，图 3.38a、3.38b